As the demand for increased performance of mail handling equipment is implemented, machine refinements are required which can accommodate and control both the faster moving mail pieces and the higher accelerations and decelerations of the machine components involved. Transport means for mail pieces and other documents of varying thicknesses have been previously devised, however one of the difficulties arising out of the use of such transport means is that as the operating speeds thereof are increased the noise and shock generated by certain portions of the varying thickness document transport means increase to objectionably high levels. These factors have to varying extents heretofore effectively limited the cyclic speeds at which mail handling apparatus may effectively operate.